1. Field of the Invention
The present invention relates to a nozzle plate for an ink jet printer and a method of manufacturing such a nozzle plate.
2. Description of the Related Art
An ink jet printer of a type in which a recording image is written onto a recording medium by ink droplets jetted from nozzles has a problem in that the direction in which each ink droplet travels deviates from a prescribed course because the vicinity of the nozzle becomes wet with ink.
To overcome this problem, a nozzle plate disclosed in Japanese Unexamined Patent Publication No. 57-107148 is designed to control the wetness of the neighborhood of the nozzle by uniformly forming by sputtering an ink-repellent coating layer, such as a fluorescent film, on both the inner surface of the nozzle and the front surface of the nozzle plate.
Keeping the vicinity of the nozzle from becoming wet with ink, the nozzle plate according to the aforementioned invention is advantageous in successfully stably splashing an ink droplet in the axial direction. However, the method of forming the ink-repellent coating employed by the aforementioned invention is not successful in making step coverage of the ink-repellent coating consistent. As a result, if the step coverage is too large and excessive, the center of vibration of the meniscus moves away from the front surface of the nozzle plate according to the degree of excess coverage. This in turn demands greater energy for jetting a predetermined amount of ink and thus deteriorates jetting efficiency. If the step coverage is too small, the center of vibration of the meniscus comes closer to the front surface of the nozzle plate, which in turn causes "misfire". That is, another ink droplet is jetted due to the meniscus being vibrated after an ink droplet has been jetted, and thus causes great inconsistency among products, impairing reliability.